Astereognosis Associated With Tumors in the Region of the Foramen Magnum

Within the last three years there were observed 2 men, each of whom had an extramedullary tumor protruding through the foramen magnum and definite unilateral astereognosis. The tumor in 1 case was verified by postmortem examination and in the other by operation. In both instances a diagnosis of lesion of the parietal lobe, contralateral to the astereognostic hand, had originally been made by those in charge. The first man had been under observation in the neurologic services of two hospitals for three months, until his death, while the other was studied in a neurosurgical service for one week before the first exploratory cerebral craniotomy, at which nothing abnormal was observed. By astereognosis I mean loss of ability to recognize by palpation the form of an object, despite the relative intactness of motor power and the primary sensory qualities of touch, temperature and pain. The person with astereognosis is unable to